Stress on Lithium-ion battery. There’s no arguing that Li-ion is superior among batteries. But a champion is not without its weakness. In fact, it’s bordering counterintuitive: Li-ion suffers from stress when dwelling at full state-of-charge (100%). And when it does so consistently month after month, its recoverable capacity will drop; though the decline may not amount to much in the short run, it does leave a dent in the battery capacity that will be a long-term thorn in your side. battery degradation (Source: Battery University – How to Prolong Lithium-based Batteries) Batteries’ recoverable capacity one year after storing at different temperatures and battery levels Adding insult to injury, it’s not even advisable to fully charge a Li-ion battery for the same reason; what’s more, prolonging it overnight? The closer it gets to 100%, the more degradation it stomachs. Generally, battery level outside the 20% – 80% range will degrade the battery more. But what could be behind this counterintuitive existence?